1. Technical Field
The disclosure relates to a position detecting system for detecting a position of a capsule medical device introduced in a subject.
2. Related Art
Conventionally, capsule medical devices have been developed for use of acquisition of various types of information regarding an inside of a subject after introduced into the subject, or for use of administration of medicines to the subject. As an example, in the field of endoscope, a capsule endoscope configured to be introduced into a digestive organ (into a lumen) of the subject has been known. The capsule endoscope has an imaging function and a wireless communication function inside a capsule-shaped casing, and captures images while moving in the digestive organ by peristaltic movement or the like, after swallowed into the subject and sequentially and wirelessly transmits image data of images (hereinafter, also referred to as in-vivo images) inside organs of the subject. The wirelessly transmitted image data is received by a receiving device provided outside the subject and is further taken in to an image processing device such as a workstation, and predetermined image processing is applied to the image data. Accordingly, in the image processing device, the in-vivo image of the subject can be reproduced in a still image or a moving image.
In addition, systems that detect a position of a capsule medical device in a subject have been developed. For example, WO 2011/102161 discloses a position detecting system that includes a coil (hereinafter, marker coil) that generates a magnetic field, in a capsule endoscope, detects the magnetic field (hereinafter, marker magnetic field) generated by the marker coil with a magnetic field detection coil (hereinafter, sensing coil) provided outside the subject, and estimates the position of the capsule endoscope, based on strength of the detected magnetic field. In this capsule endoscope, a detection value during position detection of the capsule endoscope is corrected using a detection value of the sensing coil, which has been acquired in a state where the capsule endoscope is not positioned in a space to be detected (the marker coil is in OFF state) in advance, so that an influence of an ambient environment of the position detecting system is excluded.